1. Field of the Invention
The present invention relates to a printing device including a printer function or a printer connected to a client computer through a network, and a network printing system including the printing device.
2. Related Background Art
In conventional techniques, as means for using image data for printing at an external computer, a network printing system is disclosed in JP 2001-270167 A. In this network printing system, a printing device connected to a client computer through a network converts page description language (PDL) data sent from the client computer into general-purpose print format data (intermediate format data for generating pixel map format data), holds the general-purpose print format data, converts the general-purpose print format data into pixel map format data, prints the pixel map format data, and, in response to a reference request sent from the client computer, sends the general-purpose print format data to the client computer.
In the conventional technique, in order to use the image data for printing at the client computer, the client computer needs to issue a reference request to the network printing system. There is a problem in that when the technique is used under an environment in which PDL data is asynchronously sent from an unspecified number of client computers to the printing system connected to the network, it is not easy to obtain a desired image because the client computers cannot recognize the time when desired image data is prepared at the printing system.
Further, it is difficult to determine whether an obtained image is a desired image because it is not easy to determine the client computer that has sent PDL data from which the obtained image is generated.